Pulsed Plasma Engine and Method

ABSTRACT

Pulsed plasma engine and method in which a noncombustible gas is introduced into an explosion chamber, the gas is ionized to form a plasma within the chamber, an electrical pulse is applied to the plasma to heat the plasma, the pulse is turned off to produce an explosive pressure pulse in the plasma, and the plasma is confined in the chamber by a magnetic field that directs the pressure pulse toward an output member which is driven by the pressure pulse.

RELATED APPLICATIONS

Division of Ser. No. 13/727,348, filed Dec. 26, 2012, U.S. Pat. No.8,850,809, the priority of which is claimed.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention pertains generally to engines and, more particularly, toa pulsed plasma engine and method of operating the same.

2. Related Art

A pulsed plasma engine is a type of internal explosion engine that isgenerally similar in principle to an internal combustion engine exceptthat it uses non-combustible gases such as air, oxygen, nitrogen orinert gas(es) instead of the combustible gases which are used ininternal combustion engines.

U.S. Pat. No. 7,076,950 discloses an internal explosion engine andgenerator which has a cylinder, a piston which divides the cylinder intoa pair of chambers that vary in volume in an opposite manner as thepiston travels back and forth within the cylinder, a charge ofnon-combustible gas sealed within each of the chambers, means foralternately igniting the non-combustible gas in the two chambers in anexplosive manner to drive the piston back and forth, and means coupledto the piston for providing electrical energy in response to movement ofthe piston.

Other examples of internal explosion engines are found in U.S. Pat. Nos.3,670,494 and 4,428,193.

OBJECTS AND SUMMARY OF THE INVENTION

It is, in general, an object of the invention to provide a new andimproved pulsed plasma engine and method of operating the same.

Another object of the invention is to provide a pulsed plasma engine andmethod of the above character which overcome limitations anddisadvantages of engines heretofore provided.

These and other objects are achieved in accordance with the invention byproviding a pulsed plasma engine and method in which a noncombustiblegas is introduced into an explosion chamber, the gas is ionized to forma plasma within the chamber, an electrical pulse is applied to theplasma to heat the plasma, the pulse is turned off to produce anexplosive pressure pulse in the plasma, and the plasma is confined inthe chamber by a magnetic field that directs the pressure pulse towardan output member which is driven by the pressure pulse.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of one embodiment of a power coremodule for a pulsed plasma engine incorporating the invention.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 incombination with a schematic diagram of an electrical circuit forpulsing the plasma in the embodiment of FIG. 1.

FIG. 3 is a schematic, fragmentary, vertical sectional view illustratingoperation of the embodiment of FIG. 1.

FIG. 4 is a vertical sectional view of one embodiment of a turbineengine incorporating the invention.

FIG. 5 is a vertical sectional view of another embodiment of a turbineengine incorporating the invention.

FIG. 6 is a vertical sectional view of one embodiment of a reciprocatingpiston engine incorporating the invention.

DETAILED DESCRIPTION

As illustrated in FIGS. 1 and 2, the power core has an explosion chamber11, a pair of electrodes 12, 13, a valve 14 through which anoncombustible gas such as air is introduced into the chamber, means 16for ionizing the gas to form a plasma within the chamber, a circuit 17for applying electrical pulses to the electrodes to heat the plasma andproduce explosive pressure pulses, and magnets 18, 19 for creating amagnetic field within the chamber to confine the plasma and direct thepressure pulses toward output members such as turbine wheels orreciprocating pistons (not shown) at the ends of the chamber.

The power core is constructed in the form of a generally cubical orrectangular module 21 having a central body section 22 with end pieces23, 24 on opposite sides of the central section. Axially aligned bores26-28 extend through the three sections to form the explosion chamberwhich opens through the end pieces. The bores are generally circular andof equal diameter, and the side wall of the chamber is generallycylindrical. Central body section 22 is fabricated of an insulativeceramic material such as a silicon oxide ceramic, and end pieces 23, 24are fabricated of an electrically nonconductive ceramic material of lowthermal conductivity. The three sections are held together by bolts (notshown) which pass through mounting holes 29, 30 in the central sectionand end pieces.

Electrodes 12, 13 are mounted in vertically aligned bores 31, 32 incentral body section 22, with the tips of the electrodes extending intothe explosion chamber and O-rings 33, 34 providing seals between theelectrodes and the walls of the bores. The electrodes are fabricated ofa high temperature, electrically conductive material such as tungsten orthoriated tungsten.

Valve 14 is a one-way check valve mounted in a horizontally extendingcross bore 36 that intersects and communicates with the bore for theexplosion chamber. The valve has an inlet opening 37 surrounded by avalve seat 38, with a pivotally mounted valve member 39 that is urgedinto sealing engagement with the valve seat by a spring or othersuitable means (not shown). The valve also has an outlet port 41 thatcommunicates directly with the explosion chamber, with an 0-ring 42providing a seal between the valve body and the wall of the bore. Thisvalve permits air and other gases to enter the chamber through the inletport and prevents them from escaping from the chamber.

In the embodiment illustrated, the means 16 for ionizing the gas to forma plasma comprises a radiation ionizer having a source 43 of radioactivematerial such as Americium, rubidium, or thorium in a cartridge 44mounted in a second horizontally extending cross bore 46 in central bodysection 22. This cross bore is aligned with the first, and it alsointersects the bore for the chamber. The cartridge is oriented with theradioactive material facing the chamber and an O-ring 47 providing aseal between the cartridge and the wall of the bore. Alternatively, ifdesired, the ionization can be done by other suitable means such as ahigh breakdown voltage or high frequency radiation.

Ignition circuit 17 includes a source of high energy pulses comprising atransformer 49 having a primary winding 49 a connected electrically inseries with a battery 51 and electrodes 12, 13. The winding serves as anignition coil, and a capacitor 52 is connected across the battery tostiffen the current applied to the coil. One end of the primary windingor coil is connected directly to electrode 12, and the other end isconnected to the positive terminal of the battery. The negative terminalis connected to the emitter of an insulated-gate bipolar transistor(IGBT) 53 through an ON/OFF switch 54 and a fuse 56. The collector ofthe IGBT is connected to the second electrode 13, and a pulse generator57 is connected to the gate.

A bridge rectifier 59 is included in the circuit for recharging battery51. In the embodiment illustrated, transformer 49 is an adjustabletransformer, with one input of the rectifier being connected to one endof secondary winding 49 b and the other being connected to a variabletap 61 on the secondary winding. One output of the rectifier isconnected to the positive terminal of the battery, and the other isconnected to the negative terminal.

Magnets 18, 19 are rare earth, radially polarized, permanent ringmagnets which are disposed coaxially of the explosion chamber incounterbores 63, 64 toward opposite ends of the chamber. End pieces 23,24 have axially extending cylindrical flanges 23 a, 24 a which extendinto the counterbores and are encircled by the magnets. The end piecesprovide heat shielding for the magnets and also serve as adapters formounting the module to the rest of the engine, including mounting on theblock of a conventional internal combustion engine in place of thecylinder heads. The end pieces can be configured as desired to matchdifferent engines. In the embodiment of FIGS. 1 and 2, they haveconically tapered output ports 23 b, 24 b which communicate with theexplosion chamber and open through the outer faces or mounting surfaces23 c, 24 c of the end pieces, and the power core module is affixed tothe rest of the engine by bolts (not shown) passing through mountingholes 29, 30.

Operation and use of the power core and therein the method of theinvention are as follows. Air flows into explosion chamber 11 throughcheck valve 14, and ON/OFF switch 54 is closed to turn on the ignitioncircuit, with charge from battery 51 building up on capacitor 52. Theair in the chamber is ionized by radiation from source 43 to create anelectrically conductive plasma between electrodes 12, 13. Pulses appliedto the gate of IGBT 53 by pulse generator 57 cause the IGBT to turn onand complete the circuit between transformer winding 49, the battery,and the electrodes. This causes a sudden increase in current through thewinding and produces high energy pulses which are applied to theelectrodes. The electrical current flowing through the electricallyconductive plasma between the electrodes heats the plasma to a very hightemperature, and as long as each pulse remains on, the heated plasmaremains in the gap between the electrodes. When the pulse turns off, theheat is released from the gap in an explosive manner, producing a highpressure shock pulse that can be utilized in driving an output membersuch as a turbine or a piston.

As illustrated in FIG. 3, magnet 18 is polarized with its north pole onthe inner side of the ring and the south pole on the outer side, andmagnet 19 is polarized in the opposite direction with its north pole onthe outer side and the south pole on the inner side of the ring. Themagnetic field created by the magnets confines the plasma 66 within thechamber and directs the pressure shock pulses in an axial directiontoward the ends of the chamber, as illustrated by flux lines 67.

The electrical pulses are rectangular pulses of short duration and fastrise time, and the conductivity of the plasma between the electrodes isvery high, typically greater than that of solid conductors such as gold,silver, or copper. Consequently, when the pulses are applied to theelectrodes, an arc forms immediately, and the temperature of the plasmarises very quickly. The temperature remains substantially constantthroughout the arc, with a high arc temperature of short durationproducing substantially the same pressure in the chamber as one oflonger duration.

The electrical pulses preferably have a width or duration of less than amillisecond and occur at a rate on the order of 500 to 1,000 per second,and, depending on the level of the power or energy applied, the plasmacan reach temperatures on the order of 1,000 to 100,000 ° C. innanoseconds. The arc is likewise turned off in nanoseconds ormicroseconds when the pulses are turned off. With a 100 kilowatt powersupply and a pulse width of one millisecond, for example, the energyapplied to the electrodes is on the order of 100 joules per millisecond,or 0.1 joules per microsecond.

The heat of the plasma is contained in the arc while the arc is turnedon. When the arc is turned off, the heat is explosively released fromthe arc gap, producing a shock pulse of very short duration, e.g.,microseconds.

The current flowing through the primary winding of transformer 49 toproduce the arc induces a corresponding current in secondary winding 49b which is rectified by rectifier 59 and applied to battery 51 torecharge the battery.

FIG. 4 illustrates an engine in which power core 21 drives a pair ofturbine wheels 68, 69. This engine is shown as being constructed on aplatform or base 71, with the power core mounted on a pair of supportblocks 72 affixed to the base. Turbine wheels 68, 69 are affixed tooutput shafts 73, 74 which are rotatively mounted on support blocks 76,77 affixed to the base at opposite ends of the power core. The turbinewheels are radially driven, and the output shafts are aligned with theaxis of expansion chamber 11, but perpendicular to it, with edgeportions of the wheels being received in cylindrical recesses 78, 79 inthe outer faces of end pieces 23, 24.

In operation, the axially directed pressure pulses produced by the powercore impinge radially upon the turbine blades, causing the turbinewheels and output shafts to rotate, with the pulses being delivered at arate on the order of 500-1,000 pulses per second.

FIG. 5 illustrates an embodiment in which a single axial flow turbinewheel 81 is driven by the power core. This engine is also shown as beingconstructed on a platform or base 82, with the power core mounted onsupport blocks 83 affixed to the base. Turbine wheel 81 is affixed tothe input shaft 84 a of a generator 84 which is mounted on a supportblock 86 affixed to the base at one of the power core, with shaft 84 ain axial alignment with the explosion chamber 11.

In this embodiment, power core 21 differs from the other embodiments inthat air flows into the explosion chamber through an air gap 88 and theplasma is confined by a permanent magnet 89 at the end of the chamberopposite the turbine wheel. The magnet is mounted on a support bracket91 affixed to base 82 and is spaced away from the outer face of endpiece 23 to form the air gap. Spacers 92 extend between the end pieceand magnet and help to support the magnet against the force of thepressure pulses directed toward it when the engine fires. The magnet ispolarized from front to back and is oriented with its north pole facingout and its south pole facing in so it can cooperate with ring magnet 18to form the magnetic field that confines the plasma to the chamber. Theside wall of the inlet port 23 a in end piece 23 is outwardly inclinedand rounded to facilitate the flow of air between the air gap andchamber.

In operation, air flows freely into the chamber through the air gap, butonce the air gets ionized in the chamber, the magnetic field produced bymagnet 89 and ring magnet 18 confines the plasma and prevents it fromescaping from the chamber through the air gap. As in the otherembodiments, the magnetic field produced by ring magnets 18, 19 alsoconfines the plasma and directs the pressure pulses in an axialdirection to drive turbine wheel 81 and generator 84.

In the embodiment of FIG. 6, the power core is utilized in areciprocating piston engine in which one end of explosion chamber 11 isclosed by a plug 93 and a cylinder block 94 is attached to end piece 24at the other end of the chamber. The power core module and cylinderblock are held together by bolts (not shown) that pass through alignedopenings 96, 97 in mounting tabs or lugs 93 a, 94 a that extendlaterally from end plug 93 and cylinder block 94.

A cylinder 98 within the block is aligned axially with explosion chamber11 and in direct communication with the explosion chamber through outletport 24 a in end piece 24. A piston 99 is connected to a crankshaft (notshown) by a connecting rod 101 and wrist pin 102 for reciprocatingmotion between top and bottom dead center positions, with rings 103, 104providing a pressure-tight seal between the piston and the side wall ofthe cylinder.

Means is provided for monitoring the position of the piston within thecylinder and controlling the electric pulses so that the engine firesonly when the piston is at or near its top dead center position or on adownstroke. This means includes a small magnet 106 which is mounted inthe side wall or skirt of the piston and a Hall effect sensor 107 whichis mounted on the side wall of the cylinder block toward the top of thecylinder. The sensor is connected to ignition circuit 17 to control theapplication of pulses to the electrodes.

When the piston is on a downstroke, air is drawn into explosion chamber11 through a one-way valve 14, as in the embodiments of FIGS. 1, 2, and4. When the piston reaches its top dead center position and the airbetween the electrodes is fully ionized, the Hall effect sensor connectsthe ignition circuit to the electrodes to create the arc and produce thepressure pulses in the plasma. With one end of the explosion chamberclosed by the plug, the pressure pulses produced by the exploding plasmaare all directed toward the piston to drive it toward bottom deadcenter. Before the piston reaches bottom dead center, the Hall switchdisconnects the ignition circuit from the electrodes and keeps itdisconnected until the piston reaches its top dead center positionagain.

The invention has a number of important features and advantages. Itprovides a highly efficient engine and method utilizing non-combustiblegases such as air, oxygen, nitrogen, or inert gases. The plasma producedby ionizing the gas is highly conductive and is heated to extremely hightemperatures by the intense arcing between the electrodes that occurswhen electrical pulses of short duration are applied. With pulses havinga duration or width of less than a millisecond and a rate on the orderof 500 to 1,000 per second, the plasma can reach temperatures as high as1,000 to 100,000° C. in nanoseconds. As long as the arcing continues,the heat of the plasma is contained in the arc, and when the arc isturned off, the heat is explosively released, producing powerful shockpulses which are captured and utilized in driving one or more outputmembers such as turbines or pistons.

The efficiency of the engine is enhanced significantly by use ofmagnetic confinement to control the plasma and direct the shock pulsestoward the output member(s).

Being constructed in modular form, the power core can be utilized in awide variety of engines, including conventional internal combustionengines where it can be mounted on the engine block in place of thecylinder heads and fuel system.

It is apparent from the foregoing that a new and improved pulsed plasmaengine and method have been provided. While only certain presentlypreferred embodiments have been described in detail, as will be apparentto those familiar with the art, certain changes and modifications can bemade without departing from the scope of the invention as defined by thefollowing claims.

1. A method of operating an engine to drive an output member, comprisingthe steps of: introducing a noncombustible gas into an explosion chamberwhich communicates with the output member, ionizing the gas to form aplasma within the chamber, applying an electrical pulse to the plasma toheat the plasma, turning off the pulse to produce an explosive pressurepulse in the plasma, and magnetically confining the plasma in thechamber and directing the pressure pulse toward the output member. 2.The method of claim 1 wherein the noncombustible gas is air.
 3. Themethod of claim 1 wherein the electrical pulse has a width of onemillisecond or less and is applied approximately 500-1,000 times persecond.
 4. The method of claim 1 wherein the electrical pulse is appliedto the plasma from a power supply through an isolation transformer and aswitch controlled by pulses from a pulse generator.
 5. The method ofclaim 4 wherein the power supply includes a battery which is rechargedby energy from the transformer.
 6. A method of operating an enginehaving an axially extending explosion chamber with open ends and agenerally cylindrical side wall, the steps of: introducing anoncombustible gas into the chamber, ionizing the gas to form a plasmawithin the chamber, applying an electrical pulse to electrodes withinthe chamber to heat the plasma, turning off the pulse to produce anexplosive pressure pulse in the plasma, and creating an axiallyextending magnetic field within the chamber with magnets disposedcoaxially of the chamber on opposite sides of the electrodes to confinethe plasma and direct the pressure pulse toward the open ends of thechamber.
 7. The method of claim 6 wherein the gas is introduced into thechamber through a one-way valve.
 8. The method of claim 6 including thesteps of introducing air into the chamber through an air gap, andmagnetically confining the plasma to prevent it from leaking out of thechamber through the air gap.
 9. The method of claim 6 wherein thenoncombustible gas is introduced through an inlet port that opensthrough the side wall on one side of the chamber and ionized by energyfrom ionizer mounted in a compartment that opens through the side wallon another side of the chamber.
 10. The method of claim 6 wherein aturbine wheel at one end of the chamber is driven by the pressure pulse.11. The method of claim 6 wherein a piston at one end of the chamber isdriven by the pressure pulse.
 12. A method of operating an engine todrive turbine wheels at opposite ends of an axially extending explosionchamber with a generally cylindrical side wall, the steps of:introducing a noncombustible gas into the chamber, ionizing the gas toform a plasma within the chamber, applying an electrical pulse toelectrodes within the chamber to heat the plasma, turning off the pulseto produce an explosive pressure pulse in the plasma, and creating anaxially extending magnetic field within the chamber with magnetsdisposed coaxially of the chamber on opposite sides of the electrodes toconfine the plasma and direct the pressure pulse toward the turbinewheels.
 13. The method of claim 12 wherein the noncombustible gas isair.
 14. The method of claim 12 wherein the turbine wheels rotate aboutaxes perpendicular to the chamber axis.
 15. The method of claim 12wherein the electrical pulse has a width of one millisecond or less, andsuch pulses are applied to the electrodes at a rate of approximately500-1,000 pulses per second.
 16. The method of claim 12 wherein pressurepulses are delivered to the turbine wheels at a rate on the order of500-1,000 pulses per second.